1. Field of the Invention
The present invention relates to a switched-capacitor input circuit and an analog-to-digital converter (ADC) including the same. More specifically, the present invention relates to a method and circuit for correcting an offset component of an input signal of an ADC and, more particularly, to offset correction of an input signal of a switched-capacitor ADC.
2. Description of the Related Art
As a circuit for removing an offset component of an input signal and extracting useful signal information in an ADC, a circuit having a capacitor for offset correction using a switched-capacitor circuit is known (Japanese Patent Laid-Open No. 2003-060505). This circuit performs offset correction at a desired accuracy using a necessary number of binary weighted capacitors.
The technique described in Japanese Patent Laid-Open No. 2003-060505 allows offset correction in 2n steps using n offset correction capacitors. To increase the number of steps of offset correction amount to improve the offset correction accuracy, the number of capacitors needs to be increased. This leads to an increase in the capacitor layout area.